How To: Install concrete pavers

David R. Smith

An important part of any successful landscaping project is choosing the
building materials that will provide the look and durability you desire.
Whether designing a patio or walkway, interlocking concrete pavers provide
aesthetic beauty, functionality and durability for a project that will look
great for years to come.

Versatility in design

Concrete pavers offer the color, texture and fit to overcome almost any
design challenge. Pavers are available in a variety of colors, shapes and
sizes, and you can blend textures to resemble more expensive materials
without bankrupting your budget.

Tumbled pavers, with their rough edges, have an appearance similar to stone
or slate.

Ground pavers are smooth and made to look like granite, marble, terrazzo
and other cut stones.

When installing an interlocking concrete-paver system, 90 percent of the
work involves preparation of the subsurface. In fact, you will do most of
the work on the paver project--planning, excavating and preparing the
base--before you lay a single paver.

Step 1: Planning

To begin, take some graph paper, a level and a garden hose, and start
experimenting to determine the shape and size of the project area.

Spread the garden hose around the area, using 2 x 4s to show the straight
edges. Remember that pavers offer you a great opportunity to be
adventurous. Sketch a mosaic pattern on the graph paper, or try accenting a
small pond or garden sculpture by changing patterns and colors, or add
interest by adding a border to the project.

Use the level and a 2 x 4 to check for the correct slope. For proper
drainage, the pavers should slope at a rate of 1 inch for every 5 to 8
feet. After deciding on a shape, outline 5 to 8 inches outside the pavement
edge with spray paint. The extra inches allow for adequate working space
and edging materials.

Once you determine the size and shape of the project, it's time to decide
how many pavers you need. When working on a project without many curves,
simply estimate the square footage of the space and add 5 percent. If you
have a lot of curves or a paver border, add 10 percent.

Step 2: Excavating

Keeping in mind the needed slope, now is the time to decide the finished
height of the project.

Use the bottom of a door or any permanent structure that abuts the
project as a reference.

Place stakes at varying intervals along the outline of the project.

Take a long 2 x 4 and run the board from the abutting structure to a
stake. After checking to make sure the board is level, mark the stake at
that point, and then make another mark further down the stake based on the
determined slope.

Run strings, tied to the stakes, across the length of the site to
indicate the desired finished height.

To lay an adequate amount of crushed aggregate stone base, bedding sand and
pavers, excavate the site well below the desired surface height of the
project to allow for the base and sand layers.
Simply calculate the thickness of the base, sand and paver layers to
determine the depth.

After excavating the site, compact the soil with a plate compactor to
prepare the surface for the aggregate base. Remove any standing water,
rocks or other protrusions. Any bump or depression at this or any level
will become visible in the finished project.

If the soil is clay, place a geotextile layer over the exposed soil and up
the sides of the excavated area. This will provide additional stability for
the base.

Step 3: Laying the base

If possible, use crushed rock for the base, the same material often used
under roads. The climate and type of soil under the
base determines the thickness of this layer. Cold regions with fine clay or
silt require a thicker base than well-drained soil in a warm climate.
Typically, 4 inches of base will be adequate for a patio. If any areas need
to be built up, do so with the base material. Lay the base far enough past
the true outline of the pavement so that it extends past the edge
restraints at least the same dimension as the thickness of the base (4
inches or more).
Compact the base in 3-inch layers using a mechanical plate compactor. For
best results, work the compactor in a circular motion and go over all areas
at least twice. If the base is dry, moisten it with a garden hose (but
don't saturate it) before compaction.

Step 4: Restraining the pavers

Edge restraints hold the concrete pavers and the base in place. Without
edge restraints, pavers can shift, and the base can erode. Restraints can
be made of steel, aluminum, precast concrete or plastic. Secure plastic or
metal edge restraints in place with 12-inch spikes. For projects with
several curves, you can cut the edging to follow bends in the shape of the
project.

Step 5: Setting the sand

Sand is the final layer of the base for an interlocking concrete-paver
system. For this layer, use coarse sand, such as the kind used to make
concrete. Don't use limestone screenings or stone dust. When screeded
smooth, the sand should be no thicker than 1.5 inches and perfectly smooth.

For smaller projects, drag a screed board with a 2-inch notch along the
edge restraints.

For larger projects, lay 1-inch-diameter pipes on the base and screed the
sand along the pipes.

Remove the pipes and make sure to fill in the grooves left by the pipes
with sand. Work in small areas by screeding the sand in 50- to
100-square-foot sections and lay the pavers before screeding the next
section.

Step 6: Placing the pavers

Now comes the simple part--actually laying the pavers in place. To keep
pavers in line, you can use the height string as a guide for the pattern of
the pavers. You may need to pull out and set additional strings to mark
joint lines.

Gently fit pavers tightly together in the appropriate laying pattern. When necessary along the edges, cut the pavers with a
masonry saw or mechanical splitter for a perfect fit. Lay all whole pavers
in place before adding the cut pavers. Also, always wear safety glasses
when using a masonry saw or mechanical splitter, as well as any other
safety attire recommended by the equipment manufacturer.

After you set all pavers, use the plate compactor again to vibrate and set
the pavers into the bedding sand. For the final
step, sweep sand into the joints of the new patio, driveway or path, and
compact the surface again, sweeping sand into them until the joints are
full. You can use the same coarse sand used for
bedding the pavers, but finer sand will fill joints faster. But be careful
what type of sand you use--sand that is too fine will not provide for
sufficient interlock. Make sure any sand you use is completely dry so that
it fills the cracks and provides the interlock that will keep all the
pavers in place.

A job well done
The finished product is not only aesthetically pleasing but the
interlocking concrete pavers should last 20 to 30 years. They are a
cost-effective alternative to other types of paving materials.

David R. Smith is the director of the Interlocking Concrete Pavement
Institute (Sterling, Va.).